The use of chemical gametocides for the production of new cereal grains is a rapidly expanding technology. Cereal grain such as corn, wheat, rice, rye, barley, millet, sorghum, triticale and various forage crops are the main areas where research has been undertaken to improve both the productivity and the food value of these crops. The utilization of chemical hybridization agents in this research has made possible the hybridization of cereal grain crops on economical scale. Patents which pertain to this technology include the Michael C. Seidel patents, U.S. Pat. Nos. 3,761,240; 3,838,155; and 3,576,814, which disclose N-aryl-2-oxonicotinates as male sterilants and plant growth regulators; the Glenn R. Carlson patents, U.S. Pat. Nos. 4,115,101; 4,051,142; and German Offen. No. 2,830,700, which disclose the use of N-aryl-4-oxonicotinate and N-aryl-2-oxonictonates as male sterilants; and the Taylor patent, U.S. Pat. No. 4,152,136, which discloses the use of 3-aryl-4-pyridones as herbicides. A. Selva and A. Gennaro describe in Organic Mass Spectrometry, vol. 11, pp. 117-120 (1976) the mass spectrometry data for the compound 2 -phenyl-6-methyl-3-carbethoxy-4-pyridone. No activity is disclosed for this compound.
Balogh et al., J. Het. Chem., 17, 359 (1980), disclose the synthesis of various 5-substituted (5-aryl)-1-alkyl-4-oxo-1,4-dihydro-3-pyridine carboxylic acid derivatives for antimicrobial studies.
R. Johnstone et al., Aust. J. Chem., 11, 562 (1968) (Chem. Abs., 53, 5310d (1968)) disclose 1-methyl-6-phenyl-4-pyridone-3-carboxylic acid as a decarboxylation product of a quinolone compound.
T. Kametani et al., J. Het. Chem. 14, 477 (1977) disclosed the synthesis of various 1,4-dihydro-4-oxonicotinic acid derivatives, some of which bear a 6-phenyl group, which compounds have antibacterial properties.
Wick et al., Ger. Offen. No. 2,901,868 (Chem. Abs., 91, 211273h (1979)) disclose 4-pyridone-3-carboxylic acid derivatives, for example, the 6-phenyl derivative thereof, which possess bactericidal and central nervous system stimulant properties.
Adachi, Chem-Pharm. Bull., 17 (11), 2209 (1969), discloses ring conversion reactions of isoxazolium salts, two of the products of which are ethyl 6-phenyl-1,2,5-trimethyl-4-pyridone-3-carboxylate and 6-phenyl-1,2,5-trimethyl-4-pyridone-3-carboxylic acid. No biological activity is disclosed.
Kigasawa et al., Japan Kokai No. 78 65,882 (Chem. Abs. 89, 129415f (1978)) disclose several 1,4-dihydro-4-oxonicotinic acids having antibacterial activity. Among the compounds disclosed are 6-phenyl-5-methyl-1-ethyl-1,4-dihydro-4-oxonicotinic acid, 6-methyl-5-phenyl-1-ethyl-1,4-dihydro-4-oxonicotinic acid, and 5,6-diphenyl-1-ethyl-1,4-dihydro-4-oxonicotinic acid.
The present invention relates to N-alkyl-2-aryl-4-oxonicotinates, N-alkyl-5-aryl-4-oxonicotinates, N-alkyl-6-aryl-4-oxonicotinates and N-alkyl-2,6-diaryl-4-oxonicotinates and their use as plant hybridization agents especially useful in wheat, barley and corn. These compounds are particularly active as chemical gametocides and possess a high degree of male/female selectivity. Moreover, these compounds are relatively noninjurious to both corn and wheat crops. The fact that these chemicals possess a high degree of male sterility without affecting female fertility makes them very useful as chemical gametocides.